CVE-2026-93599 rustls-webpki - Denial of Service

rustls-webpki <= 0.103.12 and 0.104.0-alpha < 0.104.0-alpha.7 contain a denial of service caused by an underflow panic in bit_string_flags() when parsing a crafted CRL with an issuingDistributionPoint extension, letting attackers cause a panic via crafted CRL input, exploit requires explicit CRL revocation checking enabled and attacker-controlled CRL bytes.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
EPSS
0.35% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Denial of Service
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
18 September 2026
Updated
15 October 2026
Weakness
CWE-191

Vendor fix

Upgrade to version 0.103.13 or 0.104.0-alpha.7 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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